Its quite normal and ok to feel a bit discombobulated (hope thats the right word) just before sending your pigs off, especially if its a first time. It never gets easier, it just becomes more normal. Surely that is good though, that you value your animals enough not to feel blase about sending them for slaughter.
When the meat comes back, well thats a whole different story. Always good to look at the carcass and to plan what I want to do with it.
Good luck, itll all be fine. HM